change the ReviewHelper for api called

app/src/main/java/fr/free/nrw/commons/review/ReviewHelper.kt

@@ -23,13 +23,17 @@ class ReviewHelper
         @JvmField @Inject
         var dao: ReviewDao? = null
 
-        /**
+
-         * Fetches recent changes from MediaWiki API
+
-         * Calls the API to get the latest 50 changes
+    /**
-         * When more results are available, the query gets continued beyond this range
+     * Gets multiple random media items for review.
-         *
+     * - Fetches recent changes and filters them
-         * @return
+     * - Checks if files are nominated for deletion
-         */
+     * - Filters out already reviewed images
+     *
+     * @param count Number of media items to fetch
+     * @return Observable of Media items
+     */
         private fun getRecentChanges() =
             reviewInterface
                 .getRecentChanges()
@@ -38,19 +42,40 @@ class ReviewHelper
                 .flatMapIterable { changes: List<MwQueryPage>? -> changes }
                 .filter { isChangeReviewable(it) }
 
-        /**
+    /**
-         * Gets a random file change for review.  Checks if the image has already been shown to the user
+     * Gets multiple random media items for review.
-         * - Picks a random file from those changes
+     * - Fetches recent changes and filters them
-         * - Checks if the file is nominated for deletion
+     * - Checks if files are nominated for deletion
-         * - Retries upto 5 times for getting a file which is not nominated for deletion
+     * - Filters out already reviewed images
-         *
+     *
-         * @return Random file change
+     * @param count Number of media items to fetch
-         */
+     * @return Observable of Media items
-        fun getRandomMedia(): Single<Media> =
+     */
-            getRecentChanges()
+    fun getRandomMediaBatch(count: Int): Observable<Media> =
-                .flatMapSingle(::getRandomMediaFromRecentChange)
+        getRecentChanges()
-                .filter { !it.filename.isNullOrBlank() && !getReviewStatus(it.pageId) }
+            .flatMapSingle(::getRandomMediaFromRecentChange)
-                .firstOrError()
+            .filter { media ->
+                !media.filename.isNullOrBlank() &&
+                        !getReviewStatus(media.pageId)
+            }
+            .take(count.toLong())
+            .onErrorResumeNext { error: Throwable ->
+                Timber.e(error, "Error getting random media batch")
+                Observable.empty()
+            }
+
+
+
+    /**
+     * Gets a random file change for review.
+     *
+     * @return Random file change
+     */
+    fun getRandomMedia(): Single<Media> =
+        getRandomMediaBatch(1)
+            .firstOrError()
+
+
 
         /**
          * Returns a proper Media object if the file is not already nominated for deletion
@@ -108,6 +133,20 @@ class ReviewHelper
                 .getGlobalUsageInfo(filename)
                 .map { it.query()?.firstPage()?.checkWhetherFileIsUsedInWikis() }
 
+
+
+
+    fun checkFileUsageBatch(filenames: List<String>): Observable<Pair<String, Boolean>> =
+        Observable.fromIterable(filenames)
+            .flatMap { filename ->
+                checkFileUsage(filename)
+                    .map { isUsed -> Pair(filename, isUsed) }
+            }
+            .onErrorResumeNext { error: Throwable ->
+                Timber.e(error, "Error checking file usage batch")
+                Observable.empty()
+            }
+
         /**
          * Checks if the change is reviewable or not.
          * - checks the type and revisionId of the change
@@ -145,5 +184,6 @@ class ReviewHelper
 
         companion object {
             private val imageExtensions = arrayOf(".jpg", ".jpeg", ".png")
+            private const val MAX_RETRIES = 3
         }
     }